More roof falls occur during the summer months than any other time of year, according to MSHA data. A recent study revealed that 80 percent of roof fall injury accidents occur under supported roof.
Historically, more roof fall accidents have occurred during the hot, humid summer months as warm air carries moisture into the mines. The moisture is absorbed into the roof strata and may weaken the roof, making it easier for the mine roof to fall. A rib roll refers to loose material that falls from a pillar or barrier of coal left for support.
"A mine's roof control plan specifies the minimum roof support required under normal conditions, but those minimum requirements no longer apply when adverse conditions are encountered," said Michael A. Davis, MSHA’s deputy assistant secretary for operations.
From June 1 through Sept. 30, 2009, MSHA inspectors will speak directly to miners and mine operators about the dangers of roof falls and rib rolls and distribute informational material providing safety guidelines for roof and rib control.
In addition, MSHA inspection personnel will talk to miners about how important it is to always conduct thorough mine examinations. Inspectors also will advise miners and mine operators to decrease roof bolt spacing when needed and use wire mesh when appropriate. Installation of wire mesh in bolted areas can prevent injury when rock falls between bolts. In addition, shorter cut depths allow the roof to be bolted sooner, helping to prevent the sag and separation of roof strata that lead to roof falls.